As shown in Japanese patent unexamined publication 2005-98003 (patent document 1), a conventional flush toilet for discharging waste by flushing the toilet with flush water is known. In the conventional toilet, the inner circumference of a rim portion formed at the top edge of the bowl portion of the flush toilet is formed to have a vertical or outward-spreading shape, whereby flush water is spouted in a horizontal direction from a water spouting port formed on the rear side of this rim portion so as to form a swirl flow, and is spouted toward a discharge trap from a jet spouting port erected at the bottom and front end of the bowl portion to generate a siphon effect, thereby discharging waste.
As shown in Japanese patent unexamined publication 2005-113643 (patent document 2), another conventional flush toilet is known. In the flush toilet, in order to improve waste discharge performance, air accumulated inside the shared water conduit of the rim water conduit and the jet water conduit at the start of flushing is removed to the outside from the rim spouting port via the rim water conduit.